The primary objective of the Zebrafish Facility is to support researchers using zebrafish to study vertebrate genefics, genomics, and development by employing expert husbandry techniques, supplying efficient and fimely services, and fostering a helpful, cooperative environment. This Core accomplishes these goals by providing the following services: (1) husbandry and feeding of adult fish, (2) husbandry and rearing of embryos and larvae, (3) provision of staged embryos, (4) sperm cryopreservation, (5) database tracking of all fish stocks and frozen sperm, (6) high through-put quaranfined screening for mutafions in fish from other facilities, (7) procedure rooms and equipment for embryo microinjecfion, and (8) advice and training on fish husbandry and facility set-up. Because our Zebrafish Facility has recently been expanded to provicle more procedure space, we are now adding a new services to the Zebrafish Facility, derivafion and maintenance of germ-free embryos and larvae.